The present invention relates to a container mixer.
A conventional container mixer comprises a mixer proper, i.e. a shaft provided with blades or the like, placed inside a container tank, and a mixer actuator, such as an electric, hydraulic or compressed-air motor, placed outside the container tank. The mixer proper and the actuator are interconnected by coupling means.
Container mixers are used in particular for stirring liquids and other corresponding fluids in container tanks. Known container mixers are usually fastened to the tank top, but they can be fastened to the tank side or even to the bottom. Container mixers are fastened to a tank top in such a manner that the actuator of the mixer remains on the top, to which it is fastened, for example, by using a flange or a mounting plate. If the container tank has a barrel thread, the mixer can be secured directly to it with binding nuts. The mixer proper, which comprises blades or the like at the end of a long shaft, is placed in the tank in a vertical position and so as to extend from the top to the inside of the tank to a point where the mixer blades produce the desired stirring effect.
Heretofore, each container tank equipped with a fixed mixer has also had its own actuator fixedly mounted on the tank. These mixer actuators project over a considerable distance above the tank, preventing two or more container tanks from being placed one on top of another during the transportation or storage of the container tanks. If it is desired to place container tanks one on top of another for reasons of saving of space, and thus reasons of cost, for the duration of storage or transportation, it has been necessary to remove the entire mixer and to close the opening in the upper section of the tank. The removal and reinstallation of the mixer is, however, time consuming, cumbersome and often dirty work. Furthermore, the detached mixer and its actuator have to be packed separately and be transported along with the container tank, which may, of course, be inconvenient.
On the other hand, it is known that mixers are needed only when the tanks are used for storing a substance which needs to be stirred. The mixer and its motor are thus not needed, for example, when the container tank is transported empty or when transporting and storing substances which are stirred only in connection with the emptying of the tank or during the discharging of the substances. A large number of mixers and actuators are thus tied down to container tanks even when they are not needed.
It is an object of the invention therefore to provide an improvement to what has been described above. It is a particular object of the invention to provide a container mixer from which the actuator, remaining outside the container, can be easily detached separately, the stirring parts proper of the container mixer remaining in place. In this case the actuator can be detached, for example, when the contents of the container tank need not be stirred, for example, when the container tank is empty or when it is being transported or when it is used for storing substances which are not stirred all the time but only in certain conditions. An object is in this case in particular to provide a container mixer which does not prevent the container tanks from being stacked.
The container mixer according to the invention comprises between the mixer and the actuator a so-called quick coupling with which the actuator of the mixer can rapidly and easily be coupled to the mixer proper and be detached from it.
The quick coupling according to the invention typically comprises a first quick coupling part fixedly connected to the mixer shaft or an extension thereof, a so-called intershaft or the like, and a second quick coupling part fixedly connected to the actuator or a part connected thereto, such as a bearing housing or the like. The quick coupling parts can be locked to each other by quick-release means, such as CAMLOCK, claw or bayonet catches.
The first quick coupling part is typically a cylindrical sleeve or housing fitted over the mixer shaft or an extension thereof, the mixer shaft being coaxially connected to it, for example by using a groove and ball bearing or the like. Thus the mixer shaft or its extension can be rotated inside the quick coupling part.
The second quick coupling part is typically also a cylindrical sleeve or housing inside which the drive shaft of the actuator, or an extension thereof, can be rotated. The quick coupling part can be connected, for example, to the bearing housing by using a threaded coupling.
A container mixer according to the invention, equipped with a quick coupling, has additionally, mounted between the actuator drive shaft and the mixer shaft or its extension, a separate shaft coupling piece, a so-called inner shaft, which transmits the rotary motion of the drive shaft to the mixer shaft. The above-mentioned quick coupling parts lock the shaft coupling piece between them, i.e. ensure its connection with both the drive shaft and the mixer shaft and the transmission of the drive shaft motion to the mixer shaft. By the opening of the quick-release means, one quick coupling part and the actuator connected thereto and the shaft coupling piece can be detached and the connection between the drive shaft and/or the mixer shaft can be disconnected.
The first (upper) end of the shaft coupling piece, which in a preferred embodiment according to the invention is made, for example, of a hexagon bar, is in the system according to the invention preferably connected coaxially to the end of the actuator drive shaft by a coaxial sleeve interconnecting the ends. This sleeve may be of rubber or some other corresponding resilient substance, in which case the coupling between the shafts is resilient. The sleeve ends correspond on the inside both in shape and in their inner diameter to the ends of the shafts to be connected by the sleeve. The sleeve diameter is typically approx. 10-25 mm, preferably approx. 15-20 mm. For example, in the case of a hexagon shaft, that end of the sleeve which is towards this shaft is on the inside hexagonal in shape or on the inside of this end of the sleeve there is fixed a ring or a cylindrical inner piece which gives the inside of the sleeve the desired hexagonal shape. Respectively, when necessary the other end of the sleeve is advantageously shaped into the shape of the drive shaft end. Typically approximately one half of the length of the shaft coupling piece, which is approx. 40-100 mm, preferably approx. 60-85 nun, protrudes inside the sleeve. In some applications it may suffice that a smaller portion, for example one-fourth or preferably, however, at least one-third, of the length of the shaft coupling piece protrudes inside the sleeve. In order to ensure the coupling between the sleeve and the shafts, the sleeve may, when necessary, be fastened by compression bindings to the drive shaft, especially if, for example, the ends of both the sleeve and the drive shaft are round in cross section. However, in such a solution according to the invention the shaft coupling piece can be easily detached from the sleeve merely by releasing the quick coupling, i.e. by opening the quick-release means and by detaching the quick coupling parts from each other.
In a solution according to the invention, the sleeve interconnecting the drive shaft and the shaft coupling piece may, on the other hand, be made of two separate cylindrical sleeve parts which are attached to the ends of the shafts. In this case the sleeve parts may be made of metal, rubber or some other suitable material. Between the metal sleeve parts there is, however, preferably left a small annular space in which there can be fitted a resilient element in order to form a resilient coupling between the coaxially fitted shaft ends. Over the sleeve parts and the resilient element there is fitted cylindrical retainer sleeve to connect them.
In a solution according to the invention, the second (lower) end of the shaft coupling piece, for example, a hexagon shaft, is preferably connected coaxially to the end of the mixer shaft by means of a sleeve-shaped intershaft interconnecting these ends. In this case the inside of that intershaft end which faces away from the mixer shaft is preferably shaped to correspond to the shape and size of the hexagon shaft so that this end of the hexagon shaft can be fitted inside the intershaft. At the other end of the intershaft there is preferably formed a thread in order to secure to it the threaded end of the mixer shaft proper.
The structure of the quick coupling is preferably such that the shaft coupling piece with its sleeve is to be mounted at least in part in the area of the cylindrical quick coupling parts of the quick coupling, inside them, whereupon the shaft coupling piece can be easily detached from the quick coupling or be placed into the quick coupling while the quick coupling parts are detached from each other, i.e. in the open position of the quick coupling.
That edge of the quick coupling part surrounding the intershaft which faces the tank is preferably provided with a thread by means of which the quick coupling part can be fastened to the top of the container tank, to its opening provided with a thread, for example, a barrel thread.
The system according to the invention provides a container mixer from which the actuator can be easily and rapidly detached by opening the quick-release means. Thus there will be left in the upper section of the container tank no detrimentally high devices which would prevent another container tank from being placed on top of the first container tank. After transportation or storage, it is possible to connect to the container mixer the actuator detached from it or another similar actuator provided with a corresponding quick coupling part. The storage and transportation of container tanks one on top of another saves in both storage and transportation costs. When the option according to the invention is used, only the mixer parts proper are fixedly installed in the container tanks. The actuator is fastened to the container tank and coupled to the mixer therein only according to need. Thus in many cases it is possible to use one and the same actuator in turns for several container mixers, in which case all in all a smaller number of actuators are needed and savings are achieved in their acquisition costs.
The invention is described below in greater detail, with reference to the accompanying drawings.